BMC/Intel-BMC/linux.git/drivers/md/dm-thin-metadata.c, branch dev-5.2

dm thin metadata: check if in fail_io mode when setting needs_check

2019-07-26T07:11:11+00:00

commit 54fa16ee532705985e6c946da455856f18f63ee1 upstream. Check if in fail_io mode at start of dm_pool_metadata_set_needs_check(). Otherwise dm_pool_metadata_set_needs_check()'s superblock_lock() can crash in dm_bm_write_lock() while accessing the block manager object that was previously destroyed as part of a failed dm_pool_abort_metadata() that ultimately set fail_io to begin with. Also, update DMERR() message to more accurately describe superblock_lock() failure. Cc: stable@vger.kernel.org Reported-by: Zdenek Kabelac Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin metadata: do not write metadata if no changes occurred

2019-04-18T20:18:34+00:00

Otherwise, just activating a thin-pool and thin device and then deactivating them will cause the thin-pool metadata to be changed (e.g. superblock written) -- even without any metadata being changed. Add 'in_service' flag to struct dm_pool_metadata and set it in pmd_write_lock() because all on-disk metadata changes must take a write lock of pmd->root_lock. Once 'in_service' is set it is never cleared. __commit_transaction() will return 0 if 'in_service' is not set. dm_pool_commit_metadata() is updated to use __pmd_write_lock() so that it isn't the sole reason for putting a thin-pool in service. Also fix dm_pool_commit_metadata() to open the next transaction if the return from __commit_transaction() is 0. Not seeing why the early return ever made since for a return of 0 given that dm-io's async_io(), as used by bufio, always returns 0. Signed-off-by: Mike Snitzer

dm thin metadata: add wrappers for managing write locking of metadata

2019-04-18T20:18:34+00:00

No functional change, but this prepares to hook off of pmd_write_lock() with additional functionality (as provided in next commit). Suggested-by: Joe Thornber Signed-off-by: Mike Snitzer

dm thin metadata: check __commit_transaction()'s return

2019-04-18T20:18:33+00:00

Fix __reserve_metadata_snap() to return early if __commit_transaction() fails. Signed-off-by: Mike Snitzer

dm thin: fix passdown_double_checking_shared_status()

2019-01-15T21:10:41+00:00

Commit 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") changed process_prepared_discard_passdown_pt1() to increment all the blocks being discarded until after the passdown had completed to avoid them being prematurely reused. IO issued to a thin device that breaks sharing with a snapshot, followed by a discard issued to snapshot(s) that previously shared the block(s), results in passdown_double_checking_shared_status() being called to iterate through the blocks double checking their reference count is zero and issuing the passdown if so. So a side effect of commit 00a0ea33b495 is passdown_double_checking_shared_status() was broken. Fix this by checking if the block reference count is greater than 1. Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared(). Fixes: 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") Cc: stable@vger.kernel.org # 4.9+ Reported-by: ryan.p.norwood@gmail.com Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm thin metadata: fix __udivdi3 undefined on 32-bit

2018-09-17T15:49:34+00:00

sector_div() is only viable for use with sector_t. dm_block_t is typedef'd to uint64_t -- so use div_u64() instead. Fixes: 3ab918281 ("dm thin metadata: try to avoid ever aborting transactions") Signed-off-by: Mike Snitzer

dm thin metadata: try to avoid ever aborting transactions

2018-09-10T21:03:18+00:00

Committing a transaction can consume some metadata of it's own, we now reserve a small amount of metadata to cover this. Free metadata reported by the kernel will not include this reserve. If any of the reserve has been used after a commit we enter a new internal state PM_OUT_OF_METADATA_SPACE. This is reported as PM_READ_ONLY, so no userland changes are needed. If the metadata device is resized the pool will move back to PM_WRITE. These changes mean we never need to abort and rollback a transaction due to running out of metadata space. This is particularly important because there have been a handful of reports of data corruption against DM thin-provisioning that can all be attributed to the thin-pool having ran out of metadata space. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm thin metadata: remove needless work from __commit_transaction

2018-06-22T18:51:11+00:00

Commit 5a32083d03fb5 ("dm: take care to copy the space map roots before locking the superblock") properly removed the calls to dm_sm_root_size() from __write_initial_superblock(). But the dm_sm_root_size() calls were left dangling in __commit_transaction(). Fixes: 5a32083d03fb5 ("dm: take care to copy the space map roots before locking the superblock") Signed-off-by: Mike Snitzer

dm thin metadata: THIN_MAX_CONCURRENT_LOCKS should be 6

2018-01-17T14:07:54+00:00

For btree removal, there is a corner case that a single thread could takes 6 locks which is more than THIN_MAX_CONCURRENT_LOCKS(5) and leads to deadlock. A btree removal might eventually call rebalance_children()->rebalance3() to rebalance entries of three neighbor child nodes when shadow_spine has already acquired two write locks. In rebalance3(), it tries to shadow and acquire the write locks of all three child nodes. However, shadowing a child node requires acquiring a read lock of the original child node and a write lock of the new block. Although the read lock will be released after block shadowing, shadowing the third child node in rebalance3() could still take the sixth lock. (2 write locks for shadow_spine + 2 write locks for the first two child nodes's shadow + 1 write lock for the last child node's shadow + 1 read lock for the last child node) Cc: stable@vger.kernel.org Signed-off-by: Dennis Yang Acked-by: Joe Thornber Signed-off-by: Mike Snitzer

dm thin metadata: call precommit before saving the roots

2017-05-15T19:09:49+00:00

These calls were the wrong way round in __write_initial_superblock. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer